EPC-3720 M7 Debug

I would like to run Cortex-M7’s FreeRtos-Hello on EPC-R3720IQ-ALA240. What are the steps? Compilation has been completed.
I tried configuring the fatload command on u-boot, but it doesn’t seem to be working. Please let me know including the UART settings.


The Pre-build image is not including the RPMSG dtb file. It can reference the Linux kernel source to create a rpmsg dts file and build dtb file for the RSB-3720. Or it can download it from the link below. I reference imx8mp-evk-rpmsg.dts and create a new “imx8mp-rsb3720-a1-rpmsg.dts” file and build the “imx8mp-rsb3720-a1-rpmsg.dtb” files.

Copy the “imx8mp-rsb3720-a1-rpmsg.dtb” to RSB-3720.

RPMSG echo str test

=> setenv fdt_file imx8mp-rsb3720-a1-rpmsg.dtb
=> fatload mmc 1:1 0x48000000 imx8mp_m7_TCM_rpmsg_lite_str_echo_rtos.bin
SD boot use mmc 1:1.
eMMC boot use mmc 2:1.
=> cp.b 0x48000000 0x7e0000 0x20000
=> bootaux 0x7e0000
=> boot

In Linux:

modprobe imx_rpmsg_tty

Test result on screenshot:
Left hand size is demo on mx8mp ROM-5722 with eMMC boot for the u-boot command.
Middle and right hand size is demo on RSB-3720.

Thank you for your reply.
I think RPMsg is not necessary if it is “freertos-hello.bin”, what do you think?
If you select MMC boot, in what location (folder) in MMC should “imx8mp_m7_TCM_rpmsg_lite_str_echo_rtos.bin” be placed?
Cortex-M7 debug messages (PRINTF) are output to COM4 (ttymxc3), but what are the settings?


  1. I don’t know what function for the “freertos-hello.bin”. If the “freertos-hello.bin” equal to “imx8mp_m7_TCM_hello_world.bin”, the RPMSG is unnecessary. I just provide the “imx8mp_m7_TCM_rpmsg_lite_str_echo_rtos.bin” demo for your reference.

  2. The image has included these files in “/run/media/mmcblk1p1”.

  3. The default M7 debug output is COM4.


  1. “freertos-hello.bin” used the sample in [SDK_2_15_000_MIMX8ML8xxxKZ]. It is probably the same as “imx8mp_m7_TCM_hello_world.bin” since it simply displays “hello-world” to COM4 (the difference is that it runs on freertos)
  2. Regarding M7 Debug Port, I am using a system [EPC-R3720IQ-ALA240] that connects UIO-4034 to EPC-R3720. COM port connector UIO2 displays the output from Cortex-A’s ttymxc3, and does not display the output from Cortex-M’s COM4. Is this switching performed using Image (DTB)? Or is it a hardware switch?

We apologize for the inconvenience, but please let us know.


The COM4 output from UIO2 connector. Our extension board UIO-4032 will connect the COM4 signal to the UIO-4032 COM_4 connector. So either you can connect a UIO-4032 board COM_4 connector for testing or you can connect the signal directory from the UIO2 for testing.

Thank you for the connection wiring diagram.
The UIO I am using is [UIO-4034]

From UIO2, I think COM2 (PIN3,5) is wired to the 9PIN connector. Am I correct in understanding that in order to use COM4, I need to connect PIN4 and 6 to the serial cable?

Hi ~

In theory, it only needs to connect PIN4, PIN6, and a GND pin for the debug console to work. I don’t test it because I have only the USB to RS-232 cables with a 9PIN connection. It can try to connect these three PINs to check if there is any output directly from it.